Of hybrid automatic repeat request (HARQ) feedback bits for polar codes

ABSTRACT

Certain aspects of the present disclosure relate to techniques and apparatus for design of hybrid automatic repeat request (HARQ) feedback bits. The method generally includes obtaining a payload to be transmitted, partitioning the payload into a plurality of blocks, and partitioning each block of the plurality of blocks into a plurality of sections. The method also includes deriving redundancy check information for each section of the plurality of sections, and generating a plurality of codewords, each comprising a block of the plurality of blocks and the redundancy check information for each section of the block, wherein a location of each of the sections in the codewords is determined based on an error rate corresponding to each of the sections.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International ApplicationPCT/CN2016/091914, filed Jul. 27, 2016 which is expressly incorporatedherein by reference in its entirety.

TECHNICAL FIELD

Certain aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, to a method and apparatus forproviding feedback.

BACKGROUND

In a transmitter of all modern wireless communication links, an outputsequence of bits from an error correcting code can be mapped onto asequence of complex modulation symbols. These symbols can be then usedto create a waveform suitable for transmission across a wirelesschannel. Particularly as data rates increase, decoding performance onthe receiver side can be a limiting factor to achievable data rates.

SUMMARY

Certain aspects of the present disclosure provide techniques andapparatus for design of hybrid automatic repeat request (HARQ) feedbackbits.

Certain aspects provide a method for wireless communications. The methodgenerally includes obtaining a payload to be transmitted, partitioningthe payload into a plurality of blocks, partitioning each block of theplurality of blocks into a plurality of sections, deriving redundancycheck information for each section of the plurality of sections, andgenerating a plurality of codewords, each comprising a block of theplurality of blocks and the redundancy check information for eachsection of the block, wherein a location of each of the sections in thecodewords is determined based on an error rate corresponding to each ofthe sections.

Certain aspects provide a method for wireless communications. The methodgenerally includes receiving a plurality of codewords, each comprising aplurality of blocks, wherein each of the plurality of blocks comprise aplurality of sections and redundancy check information for each sectionof the plurality of sections, wherein a location of each of theplurality of sections of each block is determined based on an error ratecorresponding to each of the plurality of sections of each block,decoding the plurality of sections of each block, verifying whether theplurality of sections of each block were properly decoded based on theredundancy check information for each of the decoded sections, andtransmitting an indication of whether the plurality of sections eachblock were properly decoded based on the verification.

Certain aspects provide an apparatus for wireless communications. Theapparatus generally includes at least one processor configured to obtaina payload to be transmitted, partition the payload into a plurality ofblocks, partition each block of the plurality of blocks into a pluralityof sections, derive redundancy check information for each section of theplurality of sections, and generate a plurality of codewords, eachcomprising a block of the plurality of blocks and the redundancy checkinformation for each section of the block, wherein a location of each ofthe sections in the codewords is determined based on an error ratecorresponding to each of the sections, and a memory coupled to the atleast one processor.

Certain aspects provide an apparatus for wireless communications anapparatus for wireless communication. The apparatus generally includesat least one antenna, a processing system configured to receive, via theat least one antenna, a plurality of codewords, each comprising aplurality of blocks, wherein each of the plurality of blocks comprise aplurality of sections and redundancy check information for each sectionof the plurality of sections, wherein a location of each of theplurality of sections of each block is determined based on an error ratecorresponding to each of the plurality of sections of each block, decodethe plurality of sections of each block, verify whether the plurality ofsections of each block were properly decoded based on the redundancycheck information for each of the decoded sections, and transmit, viathe at least one antenna, an indication of whether the plurality ofsections of each block was properly decoded based on the verification.

Certain aspects provide an apparatus for wireless communications. Theapparatus generally includes means for obtaining a payload to betransmitted, means for partitioning the payload into a plurality ofblocks, means for partitioning each block of the plurality of blocksinto a plurality of sections, means for deriving redundancy checkinformation for each section of the plurality of sections, and means forgenerating a plurality of codewords, each comprising a block of theplurality of blocks and the redundancy check information for eachsection of the block, wherein a location of each of the sections in thecodewords is determined based on an error rate corresponding to each ofthe sections.

Certain aspects provide an apparatus for wireless communications. Theapparatus generally includes means for receiving, via the at least oneantenna, a plurality of codewords, each comprising a plurality ofblocks, wherein each of the plurality of blocks comprise a plurality ofsections and redundancy check information for each section of theplurality of sections, wherein a location of each of the plurality ofsections of each block is determined based on an error ratecorresponding to each of the plurality of sections of each block, meansfor decoding the plurality of sections of each block, means forverifying whether the plurality of sections of each block were properlydecoded based on the redundancy check information for each of thedecoded sections, and means for transmitting an indication of whetherthe plurality of sections of each block was properly decoded based onthe verification.

Certain aspects provide a computer-readable medium having instructionsstored thereon for obtaining a payload to be transmitted, partitioningthe payload into a plurality of blocks, partitioning each block of theplurality of blocks into a plurality of sections, deriving redundancycheck information for each section of the plurality of sections, andgenerating a plurality of codewords, each comprising a block of theplurality of blocks and the redundancy check information for eachsection of the block, wherein a location of each of the sections in thecodewords is determined based on an error rate corresponding to each ofthe sections.

Certain aspects provide a computer-readable medium having instructionsstored thereon for receiving a plurality of codewords, each comprising aplurality of blocks, wherein each of the plurality of blocks comprise aplurality of sections and redundancy check information for each sectionof the plurality of sections, wherein a location of each of theplurality of sections of each block is determined based on an error ratecorresponding to each of the plurality of sections of each block,decoding the plurality of sections of each block, verifying whether theplurality of sections of each block were properly decoded based on theredundancy check information for each of the decoded sections, andtransmitting an indication of whether the plurality of sections of eachblock was properly decoded based on the verification.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 illustrates an example wireless communication system inaccordance with certain aspects of the present disclosure.

FIG. 2 illustrates a block diagram of an access point and a userterminal in accordance with certain aspects of the present disclosure.

FIG. 3 illustrates a block diagram of an example wireless device inaccordance with certain aspects of the present disclosure.

FIG. 4 is a simplified block diagram illustrating a decoder, inaccordance with certain aspects of the present disclosure.

FIG. 5 is a simplified block diagram illustrating a decoder, inaccordance with certain aspects of the present disclosure.

FIG. 6A illustrates an example structure of coded blocks of a signaltransmission.

FIG. 6B illustrates an example structure of hybrid automatic repeatrequest (HARQ) feedback bits.

FIG. 7 illustrates an example of operations for wireless communicationby a transmitter device, in accordance with certain aspects of thepresent disclosure.

FIG. 8 illustrates an example of operations for wireless communicationby a receiver device, in accordance with certain aspects of the presentdisclosure.

FIG. 9A illustrates an example structure of coded blocks segmented intotwo block groups, in accordance with certain aspects of the presentdisclosure.

FIG. 9B illustrates an example structure of HARQ feedback bits for codedblocks segmented into two block groups, in accordance with certainaspects of the present disclosure.

FIG. 10A illustrates an example structure of the coded blocks segmentedinto three block groups, in accordance with certain aspects of thepresent disclosure.

FIG. 10B illustrates an example structure of HARQ feedback bits forcoded blocks segmented into three block groups, in accordance withcertain aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that the scopeof the disclosure is intended to cover any aspect of the disclosuredisclosed herein, whether implemented independently of or combined withany other aspect of the disclosure. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects.

Although particular aspects are described herein, many variations andpermutations of these aspects fall within the scope of the disclosure.Although some benefits and advantages of the preferred aspects arementioned, the scope of the disclosure is not intended to be limited toparticular benefits, uses, or objectives. Rather, aspects of thedisclosure are intended to be broadly applicable to different wirelesstechnologies, system configurations, networks, and transmissionprotocols, some of which are illustrated by way of example in thefigures and in the following description of the preferred aspects. Thedetailed description and drawings are merely illustrative of thedisclosure rather than limiting, the scope of the disclosure beingdefined by the appended claims and equivalents thereof.

An Example Wireless Communication System

The techniques described herein may be used for various wirelesscommunication networks such as Orthogonal Frequency DivisionMultiplexing (OFDM) networks, Time Division Multiple Access (TDMA)networks, Frequency Division Multiple Access (FDMA) networks, OrthogonalFDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA) networks, CodeDivision Multiple Access (CDMA) networks, etc. The terms “networks” and“systems” are often used interchangeably. A CDMA network may implement aradio technology such as Universal Terrestrial Radio Access (UTRA),CDMA2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and Low Chip Rate(LCR). CDMA2000 covers IS-2000, IS-95 and IS-856 standards. A TDMAnetwork may implement a radio technology such as Global System forMobile Communications (GSM). An OFDMA network may implement a radiotechnology such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16(e.g., WiMAX (Worldwide Interoperability for Microwave Access)), IEEE802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM are part of UniversalMobile Telecommunication System (UMTS). Long Term Evolution (LTE) andLong Term Evolution Advanced (LTE-A) are upcoming releases of UMTS thatuse E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documentsfrom an organization named “3rd Generation Partnership Project” (3GPP).CDMA2000 is described in documents from an organization named “3rdGeneration Partnership Project 2” (3GPP2). CDMA2000 is described indocuments from an organization named “3rd Generation Partnership Project2” (3GPP2). These various radio technologies and standards are known inthe art. For clarity, certain aspects of the techniques are describedbelow for LTE and LTE-A.

The teachings herein may be incorporated into (e.g., implemented withinor performed by) a variety of wired or wireless apparatuses (e.g.,nodes). In some aspects a node comprises a wireless node. Such wirelessnode may provide, for example, connectivity for or to a network (e.g., awide area network such as the Internet or a cellular network) via awired or wireless communication link. In some aspects, a wireless nodeimplemented in accordance with the teachings herein may comprise anaccess point or an access terminal.

An access point (“AP”) may comprise, be implemented as, or known asNodeB, Radio Network Controller (“RNC”), eNodeB, Base Station Controller(“BSC”), Base Transceiver Station (“BTS”), Base Station (“BS”),Transceiver Function (“TF”), Radio Router, Radio Transceiver, BasicService Set (“BSS”), Extended Service Set (“ESS”), Radio Base Station(“RBS”), or some other terminology. In some implementations an accesspoint may comprise a set top box kiosk, a media center, or any othersuitable device that is configured to communicate via a wireless orwired medium.

An access terminal (“AT”) may comprise, be implemented as, or known asan access terminal, a subscriber station, a subscriber unit, a mobilestation, a remote station, a remote terminal, a user terminal, a useragent, a user device, user equipment, a user station, or some otherterminology. In some implementations an access terminal may comprise acellular telephone, a cordless telephone, a Session Initiation Protocol(“SIP”) phone, a wireless local loop (“WLL”) station, a personal digitalassistant (“PDA”), a handheld device having wireless connectioncapability, a Station (“STA”), or some other suitable processing deviceconnected to a wireless modem. Accordingly, one or more aspects taughtherein may be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a portable communication device, aportable computing device (e.g., a personal data assistant), a tablet,an entertainment device (e.g., a music or video device, or a satelliteradio), a television display, a flip-cam, a security video camera, adigital video recorder (DVR), a global positioning system device, or anyother suitable device that is configured to communicate via a wirelessor wired medium.

Referring to FIG. 1, a multiple access wireless communication systemaccording to one aspect is illustrated. In an aspect of the presentdisclosure, the wireless communication system from FIG. 1 may be awireless mobile broadband system based on Orthogonal Frequency DivisionMultiplexing (OFDM). An access point 100 (AP) may include multipleantenna groups, one group including antennas 104 and 106, another groupincluding antennas 108 and 110, and an additional group includingantennas 112 and 114. In FIG. 1, only two antennas are shown for eachantenna group, however, more or fewer antennas may be utilized for eachantenna group. Access terminal 116 (AT) may be in communication withantennas 112 and 114, where antennas 112 and 114 transmit information toaccess terminal 116 over forward link 120 and receive information fromaccess terminal 116 over reverse link 118. Access terminal 122 may be incommunication with antennas 106 and 108, where antennas 106 and 108transmit information to access terminal 122 over forward link 126 andreceive information from access terminal 122 over reverse link 124. In aFDD system, communication links 118, 120, 124 and 126 may use differentfrequency for communication. For example, forward link 120 may use adifferent frequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access point. In oneaspect of the present disclosure each antenna group may be designed tocommunicate to access terminals in a sector of the areas covered byaccess point 100.

In communication over forward links 120 and 126, the transmittingantennas of access point 100 may utilize beamforming in order to improvethe signal-to-noise ratio of forward links for the different accessterminals 116 and 122. Also, an access point using beamforming totransmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access point transmitting through a single antenna to all its accessterminals.

FIG. 2 illustrates a block diagram of an aspect of a transmitter system210 (e.g., also known as the access point) and a receiver system 250(e.g., also known as the access terminal) in a wireless communicationssystem, for example, a MIMO system 200. At the transmitter system 210,traffic data for a number of data streams is provided from a data source212 to a transmit (TX) data processor 214.

In one aspect of the present disclosure, each data stream may betransmitted over a respective transmit antenna. TX data processor 214formats, codes, and interleaves the traffic data for each data streambased on a particular coding scheme selected for that data stream toprovide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, m-QPSK, or m-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 222 a through 222 t. Incertain aspects of the present disclosure, TX MIMO processor 220 appliesbeamforming weights to the symbols of the data streams and to theantenna from which the symbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals may bereceived by N_(R) antennas 252 a through 252 r and the received signalfrom each antenna 252 may be provided to a respective receiver (RCVR)254 a through 254 r. Each receiver 254 may condition (e.g., filters,amplifies, and downconverts) a respective received signal, digitize theconditioned signal to provide samples, and further process the samplesto provide a corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 may be complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use.Processor 270 formulates a reverse link message comprising a matrixindex portion and a rank value portion. The reverse link message maycomprise various types of information regarding the communication linkand/or the received data stream. The reverse link message is thenprocessed by a TX data processor 238, which also receives traffic datafor a number of data streams from a data source 236, modulated by amodulator 280, conditioned by transmitters 254 a through 254 r, andtransmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights, and then processes theextracted message.

FIG. 3 illustrates various components that may be utilized in a wirelessdevice 302 that may be employed within the wireless communication systemfrom FIG. 1. The wireless device 302 is an example of a device that maybe configured to implement the various methods described herein. Thewireless device 302 may be an access point 100 from FIG. 1 or any ofaccess terminals 116, 122.

The wireless device 302 may include a processor 304 which controlsoperation of the wireless device 302. The processor 304 may also bereferred to as a central processing unit (CPU). Memory 306, which mayinclude both read-only memory (ROM) and random access memory (RAM),provides instructions and data to the processor 304. A portion of thememory 306 may also include non-volatile random access memory (NVRAM).The processor 304 typically performs logical and arithmetic operationsbased on program instructions stored within the memory 306. Theinstructions in the memory 306 may be executable to implement themethods described herein.

The wireless device 302 may also include a housing 308 that may includea transmitter 310 and a receiver 312 to allow transmission and receptionof data between the wireless device 302 and a remote location. Thetransmitter 310 and receiver 312 may be combined into a transceiver 314.A single or a plurality of transmit antennas 316 may be attached to thehousing 308 and electrically coupled to the transceiver 314. Thewireless device 302 may also include (not shown) multiple transmitters,multiple receivers, and multiple transceivers.

The wireless device 302 may also include a signal detector 318 that maybe used in an effort to detect and quantify the level of signalsreceived by the transceiver 314. The signal detector 318 may detect suchsignals as total energy, energy per subcarrier per symbol, powerspectral density and other signals. The wireless device 302 may alsoinclude a digital signal processor (DSP) 320 for use in processingsignals.

Additionally, the wireless device may also include an encoder 322 foruse in encoding signals for transmission and a decoder 324 for use indecoding received signals.

The various components of the wireless device 302 may be coupledtogether by a bus system 326, which may include a power bus, a controlsignal bus, and a status signal bus in addition to a data bus.

FIG. 4 is a simplified block diagram illustrating an encoder, inaccordance with certain aspects of the present disclosure. According tocertain aspects, the encoder 322 illustrated in FIG. 3 may comprise theencoder illustrated in FIG. 4. FIG. 4 illustrates a portion of a radiofrequency (RF) modem 404 that may be configured to provide an encodedmessage for wireless transmission. In one example, an encoder 406 in abase station (e.g., BS 110 and/or 210) (or an access terminal on thereverse path) receives a message 402 for transmission. The message 402may contain data and/or encoded voice or other content directed to thereceiving device. The encoder 406 encodes the message using a suitablemodulation and coding scheme (MCS), typically selected based on aconfiguration defined by the base station 110/210 or another networkentity. In some cases, the encoder 406 may encode the message usingtechniques described below (e.g., by using a convolutional code). Anencoded bitstream 408 produced by the encoder 406 may then be providedto a mapper 410 that generates a sequence of Tx symbols 412 that aremodulated, amplified and otherwise processed by Tx chain 414 to producean RF signal 416 for transmission through antenna 418.

FIG. 5 is a simplified block diagram illustrating a decoder, inaccordance with certain aspects of the present disclosure. According tocertain aspects, the decoder 324 illustrated in FIG. 3 may comprise thedecoder illustrated in FIG. 5. FIG. 5 illustrates a portion of a RFmodem 510 that may be configured to receive and decode a wirelesslytransmitted signal including an encoded message (e.g., a message encodedusing a convolutional code as described below). In various examples, themodem 510 receiving the signal may reside at the access terminal, at thebase station, or at any other suitable apparatus or means for carryingout the described functions. An antenna 502 provides an RF signal 416(i.e., the RF signal produced in FIG. 4) to an access terminal (e.g.,access terminal 116, 118, and/or 250). An RF chain 506 processes anddemodulates the RF signal 418 and may provide a sequence of symbols 508to a demapper 512, which produces a bitstream 514 representative of theencoded message.

A decoder 516 may then be used to decode m-bit information strings froma bitstream that has been encoded using a coding scheme (e.g., aconvolutional code). The decoder 516 may comprise a Viterbi decoder, analgebraic decoder, a butterfly decoder, or another suitable decoder. Inone example, a Viterbi decoder employs the well-known Viterbi algorithmto find the most likely sequence of signaling states (the Viterbi path)that corresponds to a received bitstream 514. The bitstream 514 may bedecoded based on a statistical analysis of LLRs calculated for thebitstream 514. In one example, a Viterbi decoder may compare and selectthe correct Viterbi path that defines a sequence of signaling statesusing a likelihood ratio test to generate LLRs from the bitstream 514.Likelihood ratios can be used to statistically compare the fit of aplurality of candidate Viterbi paths using a likelihood ratio test thatcompares the logarithm of a likelihood ratio for each candidate Viterbipath (i.e. the LLR) to determine which path is more likely to accountfor the sequence of symbols that produced the bitstream 514. The decoder516 may then decode the bitstream 514 based on the LLRs to determine themessage 518 containing data and/or encoded voice or other contenttransmitted from the base station (e.g., BS 110 and/or 210). The decodermay decode the bitsteam 514 in accordance with aspects of the presentdisclosure presented below.

Example Hybrid Automatic Repeat Request (Harq) Feedback Bits For PolarCodes

Aspects of the present disclosure are generally directed to an efficientdesign of hybrid automatic repeat request (HARQ) feedback bits for Polarcodes by considering the sorting of channels based on the bit-errorprobability.

Polar codes were invented in 2007 and are the first codes with anexplicit construction to provably achieve the channel capacity forsymmetric binary-input discrete memoryless channels. The capacity can beachieved with a simple successive cancellation (SC) decoder. Polar codesand low-density parity check (LDPC) codes are two competitive candidatesfor 5G channel coding.

Polar codes are block codes. The generate matrices of polar codes arethe submatrices of Hadamard matrices. To construct polar codes, the rowsof the Hadamard matrices corresponding to the good channels (e.g.,having low bit-error probability) may be selected for information bits.The bad channels (e.g., having high bit-error probability) may be usedfor frozen bits with fixed value of zeros. In a practical system,density evolution or Gaussian approximation is generally used todetermine the bit-error probability of each channel. The bit-errorprobabilities of all the channels may be sorted. If N information bitsare desired, the best N channels (with low bit-error probability) areselected for information bits while the remaining channels aredesignated for frozen bits. If the information blocks are divided intoseveral equal sub-blocks, the block error rate of the sub-blocks closeto the best channel should be lower than that close to the worstchannel. HARQ scheme is widely used in wireless communication systems toimprove transmission efficiency. HARQ scheme generally includes theretransmission of coded blocks that are not decoded correctly at areceiver. Aspects of the present disclosure use this property for anefficient design of HARQ feedback.

FIG. 6A illustrates an example structure 600 of coded blocks of a signaltransmission. A large transport block (TB) may be segmented into severalsmall sub-blocks (e.g., if the TB size is larger than 6144 bits), suchas block 1 to block n. In some cases, there may be a single cyclicredundancy check (CRC) attached for all the bits in the transport block.The CRC may be used to determine if the TB is decoded correctly. TheHARQ feedback bit is generated based on the decoding result. In certainaspects, each of the sub-blocks may be encoded as one codeword and eachof the codewords may include a CRC for early termination.

FIG. 6B illustrates an example structure 602 of HARQ feedback bits. Asillustrated in FIG. 6A, a TB may be segmented into several blocks andeach block may be encoded as one codeword. As presented above, a CRC maybe attached for each block and may be used for early termination. Inthis case, only a single bit may be used foracknowledgement/no-acknowledgement (ACK/NACK). That is, a NACK may beobtained by a transmitter for an entire block even if only one sub-blockwas not decoded correctly at the receiver. In this case, all thesub-blocks may be retransmitted again as the transmitter would not beable to know which sub-blocks were not decoded correctly, resulting inwasted resources. Moreover, it may be difficult for the receiver to feedback the CRC result for each block to the transmitter due to a largenumber of ACK/NACK bits associated with this option.

In 5G wireless communication systems, the desired data rate is high. Toprovide high data rate, a large size TB (e.g., with up to one millionbits) may be implemented. If all the coded blocks are retransmitted whenmajority of them are decoded correctly, a significant amount ofresources may be wasted.

Aspects of the present disclosures provide a more efficient HARQfeedback process. For example, polar codes may be used to divide codedblocks into several groups and a bit may be used to indicate the overalldecoding results of each group. This way, multiple feedback bits may beused to signal the decoding results of the groups. If the blocks in agroup are decoded correctly, that group may not be retransmitted, savingresources.

FIG. 7 illustrates example operations 700 for wireless communications,in accordance with certain aspects of the present disclosure. Accordingto certain aspects, operations 700 may be performed by a wirelesstransmission device (e.g., wireless device 302).

Operations 700 begin at 702 by obtaining a payload to be transmitted. At704, the wireless transmission device partitions the payload into aplurality of blocks. At 706, the wireless transmission device partitionseach block of the plurality of blocks into a plurality of sections, andat 708, derives redundancy check information for each section of theplurality of sections. At 710, the wireless transmission devicegenerates a plurality of codewords, each comprising a block of theplurality of blocks and the redundancy check information for eachsection of the block, wherein a location of each of the sections in thecodewords is determined based on an error rate corresponding to each ofthe sections.

FIG. 8 illustrates example operations 800 for wireless communications,in accordance with certain aspects of the present disclosure. Accordingto certain aspects, operations 800 may be performed by a wirelessreception device (e.g., wireless device 302). According to certainaspects, operations 800 may be complimentary to the operations 700. Forexample, operations 700 may be performed by wireless transmission devicefor generating (and transmitting) a codeword and operations 800 may beperformed by a wireless reception device for receiving and decoding thecodeword.

Operations 800 begin at 802 by receiving a plurality of codewords, eachcomprising a plurality of blocks, wherein each of the plurality ofblocks comprise a plurality of sections and redundancy check informationfor each section of the plurality of sections, wherein a location ofeach of the plurality of sections of each block is determined based onan error rate corresponding to each of the plurality of sections of eachblock. At 804, the wireless reception device decodes the plurality ofsections of each block. At 806, the wireless reception device verifieswhether the plurality of sections of each block were properly decodedbased on the redundancy check information for each of the decodedsections. At 808, an indication of whether the plurality of sections ofeach block was properly decoded is transmitted based on theverification.

FIG. 9A illustrates an example structure 900 of the coded blockssegmented into two groups, in accordance with certain aspects of thepresent disclosure. As presented above, if a TB size is larger than athreshold (for example, 8000 bits), the TB may be segmented into severalblocks and each block may be encoded as one codeword. A CRC may beattached for each block, as illustrated. There are several purposes forthe CRC. For example, the CRC can be used to determine if thecorresponding block is decoded correctly. Moreover, the CRC may be usedfor CRC-aided successive cancellation list (CA-SCL) decoding to providebetter performance.

In each codeword, all the bit-channels may be sorted from best channelto worst channel according to a respective bit-error probability of thechannels. In some aspects, the bit-error probability may be obtained bydensity evolution or Gaussian approximation. For example, theinformation bits and CRC may be divided into two groups A and B. Group Amay have a lower block error rate as compared to group B. Each codewordmay include the CRC bits for group A, data for group A, the CRC bits forgroup B, and the data for group B. Frozen bits may be allocated to oneor more channels having the lowest bit-error probability (worstchannels). Therefore, the block error rate of group A may be lower thanthe error rate of group B. Each coded block may be obtained bybit-reversal permutation and encoding.

FIG. 9B illustrates an example structure 902 of HARQ feedback bits(e.g., for polar codes) for coded blocks segmented into two blockgroups, in accordance with certain aspects of the present disclosure. Asillustrated, two feedback bits may be used to indicate four possiblecases. The result of group A or group B may be indicated separately.Thus, it is possible for a transmitter to choose an efficient way torealize HARQ. For example, if the transmitter receives feedback bits as“10”, this implies that the codewords in group A are decoded correctly.In this case, the transmitter may prepare the retransmission based ongroup B without considering group A. For HARQ with chase combining, onlythe codewords in group B may be retransmitted. In this case, only halfof the resources may be used as compared to the existing design offeedback bits. For HARQ with increment redundancy, this also allows fora more efficient way for retransmission in the case where group A isdecoded correctly.

FIG. 10A illustrates an example structure 1000 of the coded blockssegmented into three groups, in accordance with certain aspects of thepresent disclosure. There is a CRC attached for all the bits in the TB.The CRC is used to determine if the TB is decoded correctly. The HARQfeedback bits are generated based on the decoding results of the TB. Ifthe TB size is larger than a threshold (e.g., 8000 bits), the TB may besegmented into several blocks and each block may be encoded as onecodeword, as illustrated. A CRC is attached for each block.

As presented above, there may be two purposes for the CRC. First, theCRC can be used to determine if the corresponding block is decodedcorrectly. Second, the CRC may be used for CRC-aided successivecancellation list (CA-SCL) decoding to provide better performance. Ineach codeword, all the bit-channels may be sorted from best channel toworst channel according to the bit-error probability. The bit-errorprobability may be obtained by density evolution or Gaussianapproximation.

In this case, the information bits and CRC attached are divided intothree groups: group A with lowest block error rate, group B with lowblock error rate (e.g., higher than group B but lower than group C) andgroup C with highest block error rate. Each codeword may include CRCbits for group A, data for group A, CRC bits for group B, data for groupB, CRC bits for group C, data for group C. Moreover, frozen bits may beallocated to one or more channels having the lowest bit-errorprobability (worst channels). Therefore, the block error rate of group Amay be lower than that of group B and the block error rate of group Bmay be lower than that of group C. Each coded block is obtained bybit-reversal permutation and encoding.

FIG. 10B illustrates an example structure 1002 of HARQ feedback bits(e.g., for polar codes) for coded blocks segmented into three blockgroups, in accordance with certain aspects of the present disclosure.For three groups, three bits may be used for HARQ feedback, each bitcorresponding to one of the three groups. However, aspects of thepresent disclosure may use two feedback bits instead of three. That is,the number of feedback bits can be reduced by considering therelationship among the block error rates of group A, group B, and groupC. Since block error rate of group A is lower than that of group B andblock error rate of group B is lower than that of group C, theprobability that group A is not decoded correctly while group B or groupC is decoded correctly is low. Similarly, the probability that group Bis not decoded correctly while group C is decoded correctly is low.

Therefore, aspects of the present disclosure provide an efficient designof HARQ feedback using two bits for three groups by eliminating thecases with low probability. For example, if the transmitter receivesfeedback bits “10”, this implies that the codewords in group A and groupB are decoded correctly. The transmitter will prepare the retransmissionbased on group C without considering group A and group B. For HARQ withchase combining, only the codewords in group C may be retransmitted. Inthis case, only one third of the resources may be used as compared tothe existing design of feedback bits. For HARQ with incrementredundancy, it is also easy to find an efficient way for retransmissionon condition that the group A and group B are decoded correctly.

While examples provided herein have described HARQ feedback withcodewords segmented into two groups and three groups to facilitateunderstanding, the techniques provided herein may be applied tocodewords segmented into any number of groups. For example, in a casewhere the coded blocks are segmented into four block groups (groupsA-D), the number of feedback bits can be reduced by considering therelationship among the block error rates of group A-D, similar to theaspects described with three groups.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor.

For example, means for processing, means for generating, means forobtaining, means for partitioning, means for determining, means forderiving, means for merging, means for verifying, means forconcatenating, means for interleaving, means for decoding, and means forencoding may comprise a processing system, which may include one or moreprocessors, such as the TX data processor 214, the processor 230, and/orthe RX data processor 242 of the access point 210 illustrated in FIG. 2or the TX data processor 238, the processor 270, and/or the RX dataprocessor 260 of the user equipment 250 illustrated in FIG. 2.Additionally, means for transmitting and means for receiving maycomprise a TMTR/RCVR 224 of the access point 210 or a TMTR/RCVR 252 ofthe user equipment 250.

According to certain aspects, such means may be implemented byprocessing systems configured to perform the corresponding functions byimplementing various algorithms (e.g., in hardware or by executingsoftware instructions) described above.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and/or write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary embodiments, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and BLU-RAY®media disc where disks usually reproduce data magnetically, while discsreproduce data optically with lasers. Combinations of the above shouldalso be included within the scope of computer-readable media.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein, but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for wireless communications, comprising:obtaining a payload to be transmitted; partitioning the payload into aplurality of blocks; partitioning each block of the plurality of blocksinto a plurality of sections; deriving redundancy check information foreach section of the plurality of sections; generating a plurality ofcodewords, each comprising a block of the plurality of blocks and theredundancy check information for each section of the block, wherein thesections in a respective codeword of the plurality of codewords arearranged in the codeword based on an error rate corresponding to each ofthe sections; transmitting the plurality of codewords to a wirelessnode; and receiving feedback from the wireless node indicating whetherthe plurality of sections of each block were decoded by the wirelessnode, wherein the feedback comprises one or more bits.
 2. The method ofclaim 1, wherein the plurality of sections of each block comprises afirst section, a second section, and a third section, and wherein thefirst section of each block has a lower error rate than the secondsection of each block and the second section of each block has a lowererror rate than the third section of each block.
 3. The method of claim2, wherein: receiving the feedback comprises receiving an indicationthat the first section of each block or the second section of each blockwas not decoded; the method further comprises: determining whether thethird section of each block was decoded based on the indication; andretransmitting the third section of each block based on thedetermination.
 4. The method of claim 1, wherein the plurality ofsections of each block comprises at least three sections, and whereinthe indication comprises a fewer number of bits than a number ofsections of each block.
 5. The method of claim 1, wherein: receiving thefeedback comprises receiving an indication that two sections of eachblock were not decoded, wherein the indication comprises a bitcorresponding to each of the two sections; and the method furthercomprises re-transmitting the two sections of each block based on theindication.
 6. The method of claim 1, wherein the redundancy checkinformation comprises a cyclic redundancy check (CRC).
 7. The method ofclaim 1, wherein the codewords are encoded using polar coding.
 8. Amethod for wireless communications, comprising: receiving a plurality ofcodewords, each comprising a plurality of blocks, wherein each of theplurality of blocks comprises a plurality of sections and redundancycheck information for each section of the plurality of sections, whereinthe plurality of sections in a respective codeword of the plurality ofcodewords are arranged in the codeword based on an error ratecorresponding to each of the plurality of sections of each block;decoding the plurality of sections of each block; verifying whether theplurality of sections of each block were decoded based on the redundancycheck information for each of the decoded sections; and transmittingfeedback comprising an indication of whether the plurality of sectionsof each block was decoded based on the verification, wherein thefeedback comprises one or more bits.
 9. The method of claim 8, whereinthe plurality of sections of each block comprises at least threesections, and wherein the indication comprises a fewer number of bitsthan a number of sections of the plurality of sections.
 10. The methodof claim 8, wherein the plurality of sections of each block comprises afirst section, a second section, and a third section, and wherein thefirst section of each block has a lower error rate than the secondsection of each block and the second section of each block has a lowererror rate than the third section of each block.
 11. The method of claim10, wherein the indication comprises a first bit used to indicatewhether the second section of each block was decoded and a second bitused to indicate whether the third section of each block was decoded.12. The method of claim 8, further comprising: transmitting anindication of whether two sections of each block were decoded based onthe verification, wherein the indication comprises a bit correspondingto each of the two sections.
 13. The method of claim 8, wherein theredundancy check information comprises a cyclic redundancy check (CRC).14. The method of claim 8, wherein the decoding comprises performingCRC-aided successive cancellation list (CA-SCL) decoding based on theredundancy check information.
 15. The method of claim 8, wherein thecodewords are encoded using polar coding.
 16. An apparatus for wirelesscommunications, comprising: means for obtaining a payload to betransmitted; means for partitioning the payload into a plurality ofblocks; means for partitioning each block of the plurality of blocksinto a plurality of sections; means for deriving redundancy checkinformation for each section of the plurality of sections; means forgenerating a plurality of codewords, each comprising a block of theplurality of blocks and the redundancy check information for eachsection of the block, wherein the sections in a respective codeword ofthe plurality of codewords are arranged in the codeword based on anerror rate corresponding to each of the sections; means for transmittingthe plurality of codewords to a wireless node; and means for receivingfeedback from the wireless node indicating whether the plurality ofsections of each block were decoded by the wireless node, wherein thefeedback comprises one or more bits.
 17. The apparatus of claim 16,wherein the plurality of sections of each block comprises a firstsection, a second section, and a third section, and wherein the firstsection of each block has a lower error rate than the second section ofeach block and the second section of each block has a lower error ratethan the third section of each block.
 18. The apparatus of claim 17,wherein: the means for receiving feedback comprises means for receivingan indication that the first section of each block or the second sectionof each block was not decoded; the apparatus further comprising: meansfor determining whether the third section of each block was decodedbased on the indication; and means for retransmitting the third sectionof each block based on the determination.
 19. The apparatus of claim 16,wherein the plurality of sections of each block comprise at least threesections, and where the indication comprises a fewer number of bits thana number of sections of each block.
 20. The apparatus of claim 16,wherein: the means for receiving the feedback comprises means forreceiving an indication that two sections of each block were notdecoded, wherein the indication comprises a bit corresponding to each ofthe two sections; and the apparatus further comprises means forre-transmitting the two sections of each block based on the indication.21. The apparatus of claim 16, wherein the redundancy check informationcomprises a cyclic redundancy check (CRC).
 22. The apparatus of claim16, wherein the codewords are encoded using polar coding.
 23. Anapparatus for wireless communications, comprising: means for receiving aplurality of codewords, each comprising a plurality of blocks, whereineach of the plurality of blocks comprises a plurality of sections andredundancy check information for each section of the plurality ofsections, wherein the plurality of sections in a respective codeword ofthe plurality of codewords are arranged in the codeword based on anerror rate corresponding to each of the plurality of sections of eachblock; means for decoding the plurality of sections of each block; meansfor verifying whether the plurality of sections of each block weredecoded based on the redundancy check information for each of thedecoded sections; and means for transmitting feedback comprising anindication of whether the plurality of sections of each block wasdecoded based on the verification, wherein the feedback comprises one ormore bits.
 24. The apparatus of claim 23, wherein the plurality ofsections of each block comprises at least three sections, and whereinthe indication comprises a fewer number of bits than a number ofsections of the plurality of sections.
 25. The apparatus of claim 23,wherein the plurality of sections of each block comprises a firstsection, a second section, and a third section, and wherein the firstsection of each block has a lower error rate than the second section ofeach block and the second section of each block has a lower error ratethan the third section of each block.
 26. The apparatus of claim 25,wherein the indication comprises a first bit used to indicate whetherthe second section of each block was decoded and a second bit used toindicate whether the third section of each block was decoded.
 27. Theapparatus of claim 23, further comprising: means for transmitting anindication of whether two sections of each block were decoded based onthe verification, wherein the indication comprises a bit correspondingto each of the two sections.
 28. The apparatus of claim 23, wherein theredundancy check information comprises a cyclic redundancy check (CRC).29. The apparatus of claim 23, wherein the means for decoding comprisesmeans for performing CRC-aided successive cancellation list (CA-SCL)decoding based on the redundancy check information.
 30. The apparatus ofclaim 23, wherein the codewords are encoded using polar coding.